Have you ever seen the inside of a piece of wood and noticed the little round circles in the middle? These layers are growth rings, also known as tree rings. In areas like North America, which has distinct seasons, the growth rings form lighter rings early in the season when it is warm and wet and darker rings later in the year when it is cold and dry. We can use these growth rings to look at changes in past climate. For example, when it is wetter, the rings are thicker and when it is drier, the rings get thinner. We can then start to look at older trees to reconstruct what climate was like in the past.
There has been a long-standing assumption that dendrochronology can not be done in the tropics because it is always wet and there is not enough difference in the seasons, thus the trees would not make individual rings. However, recently, researchers have show that some species in the seasonally dry tropical forests do in fact make annual rings.
The first component of our project: Jamaica a Last Frontier, will be to collect tree rings throughout the southern coast of Jamaica. Dr Adam Csank is here from the University of Reno as our Teams dendrochronology expert. Today we had an excellent tree coring lesson with our new tree corer Busi (short for Busera simaruba, or Red Birch which the key species of interest in our study). We selected Red Birch because it is one of the species shown to have annual layers.
One of the cool things about tree coring is that it does not kill the tree. Adam says it like a tree biopsy. Thus we can study the tree rings without causing damage to the tree. Tomorrow we head to the field to try our hand in dendrochronology. Stay tuned for more adventures to come.